Class 9 Exam > Class 9 Questions > A man is moving with 36 kmph. The time of rea... Start Learning for Free
A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:
- a)19 m
- b)17 m
- c)16 m
- d)18 m
Correct answer is option 'A'. Can you explain this answer?
Most Upvoted Answer
A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On ...
Given :
u = 36 km/h = 36x (5/18) = 10 m/s
Time of reaction, t = 0.9 s
decelration, a = -5 m/s^2
v = 0 m/s
Let s1 be the distance covered by man when the object is seen by him
we have, u = s1/t
because s1 = u x t
= 10 x 0.9
= 9 m
when he applies brakes and decelerates at the rate of 5 m/s^2, the distance covered by him is s2
We have, v^2 = u^2 + 2as2
therefore 0 = u^2 - 2as2 ( therefore v=0 m/s)
therefore s2 = u^2/2a = 10^2/ (2 x 5)
therefore s2 =10 m
So, total distance covered s = s1 + s2 = 9 +10 =19 m
Hence 19 m distance covered by man before he stops.
Free Test
FREE
| Start Free Test |
Community Answer
A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On ...
To find the total distance covered before the man stops, we need to consider two main factors: the distance covered during the reaction time and the distance covered while decelerating.
1. Distance covered during reaction time:
The man is moving at a speed of 36 km/h, which can be converted to m/s by multiplying it by 5/18. So, his initial speed is (36 × 5/18) = 10 m/s.
The reaction time is given as 0.9 seconds. During this time, the man will continue moving at his initial speed.
Therefore, the distance covered during the reaction time is calculated by multiplying the initial speed by the reaction time: (10 × 0.9) = 9 m.
2. Distance covered while decelerating:
The man applies the brakes and decelerates at a rate of 5 m/s^2.
The formula to calculate the distance covered while decelerating is given by:
Distance = (Initial velocity × Time) + (1/2 × Deceleration × Time^2)
In this case, the initial velocity is 10 m/s, and the deceleration is -5 m/s^2 (negative because it is opposite to the direction of motion).
To find the time it takes for the man to stop, we can use the formula:
Final velocity = Initial velocity + (Deceleration × Time)
Since the final velocity is 0 m/s (as the man stops), we can substitute the values and solve for time:
0 = 10 - (5 × Time)
5 × Time = 10
Time = 2 seconds
Using this value of time, we can calculate the distance covered while decelerating:
Distance = (10 × 2) + (1/2 × -5 × 2^2)
Distance = 20 - 10
Distance = 10 m
Therefore, the total distance covered before the man stops is the sum of the distance covered during the reaction time and the distance covered while decelerating:
Total distance = Distance covered during reaction time + Distance covered while decelerating
Total distance = 9 + 10
Total distance = 19 m
Hence, the correct answer is option 'A', 19 m.
1. Distance covered during reaction time:
The man is moving at a speed of 36 km/h, which can be converted to m/s by multiplying it by 5/18. So, his initial speed is (36 × 5/18) = 10 m/s.
The reaction time is given as 0.9 seconds. During this time, the man will continue moving at his initial speed.
Therefore, the distance covered during the reaction time is calculated by multiplying the initial speed by the reaction time: (10 × 0.9) = 9 m.
2. Distance covered while decelerating:
The man applies the brakes and decelerates at a rate of 5 m/s^2.
The formula to calculate the distance covered while decelerating is given by:
Distance = (Initial velocity × Time) + (1/2 × Deceleration × Time^2)
In this case, the initial velocity is 10 m/s, and the deceleration is -5 m/s^2 (negative because it is opposite to the direction of motion).
To find the time it takes for the man to stop, we can use the formula:
Final velocity = Initial velocity + (Deceleration × Time)
Since the final velocity is 0 m/s (as the man stops), we can substitute the values and solve for time:
0 = 10 - (5 × Time)
5 × Time = 10
Time = 2 seconds
Using this value of time, we can calculate the distance covered while decelerating:
Distance = (10 × 2) + (1/2 × -5 × 2^2)
Distance = 20 - 10
Distance = 10 m
Therefore, the total distance covered before the man stops is the sum of the distance covered during the reaction time and the distance covered while decelerating:
Total distance = Distance covered during reaction time + Distance covered while decelerating
Total distance = 9 + 10
Total distance = 19 m
Hence, the correct answer is option 'A', 19 m.
 | Explore Courses for Class 9 exam |  |
Top Courses for Class 9View all
Top Courses for Class 9
Question Description
A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer? for Class 9 2026 is part of Class 9 preparation. The Question and answers have been prepared according to the Class 9 exam syllabus. Information about A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for Class 9 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer?.
A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer? for Class 9 2026 is part of Class 9 preparation. The Question and answers have been prepared according to the Class 9 exam syllabus. Information about A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for Class 9 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer?.
Solutions for A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer? in English & in Hindi are available as part of our courses for Class 9. Download more important topics, notes, lectures and mock test series for Class 9 Exam by signing up for free.
Here you can find the meaning of A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer?, a detailed solution for A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer? has been provided alongside types of A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:a)19 mb)17 mc)16 md)18 mCorrect answer is option 'A'. Can you explain this answer? tests, examples and also practice Class 9 tests.
| Explore Courses for Class 9 exam | |
Top Courses for Class 9
Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
